A common foundry induction furnace comprises a cylindrical outer wall, typically including an induction heating coil, and a continuous lining formed of sintered silica or other refractory material defining a chamber for containing molten metal, such as an iron melt. From time to time, the lining becomes eroded and requires replacement. Following removal of the worn lining, an expendable steel cylindrical form is concentrically installed within the furnace spaced apart from the outer wall so as to define an annular space. Refractory particles are supplied in bags and manually poured into the space. This refractory is sintered first by gas heaters fired into the furnace, and thereafter by an initial charge of molten iron melted within the furnace. The initial charge also melts the expendable form to reveal the sintered lining.
Manual dumping of the particles from bags into the space is a dirty, laborious and time-consuming job. Workers are required to wear bulky protective clothing and use respirators. Also, air tends to be entrapped in the particulate body to produce voids in the lining that physically weaken the lining or create pockets of overheated metal.
It is an object of this invention to provide an apparatus for conveniently and quickly dispensing particulate material into an annular space, such as, in a preferred embodiment, the space between a foundry furnace outer wall and an expendable steel form during operations to form a continuous, sintered refractory lining. The apparatus evenly and continuously distributes the particulate material in a helical pattern to progressively and uniformly fill the space.